List friends: great topic. I went to our local Theatrical supply store. Picked up a solid sheet {no seams} of Muslin that measured out 9' 6" square. I washed it in hot water, ran it through the drier, then put it in a 55 gal. drum of walnut hulls, got some nice color in it, then layed it out flat on the driveway and sprayed on, with a fruit sprayer, "Canvak", and this gave a clear waterproofing that has turned out the rain like a duck. Re-inforced the corners prior to dying. Going on 8 years strong, no problems...kent Klein